The present invention relates to the dispensing of attachments and more particularly to the dispensing of attachments from continuously connected ladder stock.
In commonly assigned U.S. Pat. No. 4,039,078, which is incorporated herein by reference, there are disclosed several different types of attachments which are fabricated as part of continuously connected ladder stock. In each instance, the attachment has an H-shape, and the ladder stock is formed from two elongated and continuous plastic side members coupled together by a plurality of plastic cross links, the cross links preferably being equidistantly spaced. The stock may be produced from flexible plastics material including nylon, polypropylene and other similar materials by molding or by stamping. Either manually or with the aid of specifically designed devices, individual attachments may be dispensed from the ladder stock to couple buttons to fabric, mechandising tags to articles of commerce, or, in general, any two desired articles. In those instances where the dispensing device has dual needles, the attachments severed from the stock can be used like staples to secure objects and items.
In commonly assigned U.S. Pat. No. 4,877,172, which is also incorporated herein by reference, a device for dispensing attachments of the type described above is disclosed. The device disclosed therein includes a reciprocatively mounted shuttle which fixedly carries a pair of hollow slotted needles and which moves between an attachment severing position and an attachment dispensing position. A feed belt, which is driven by a pair of sprockets, is sued to incrementally advance the ladder stock so that, at the end of each attachment dispensing cycle, a single attachment is fed into the needles at the attachment severing location. Once the attachment has been fed into the pair of needles, a slidably mounted knife blade severs the attachment from the remainder of the ladder stock, and the shuttle is moved to the attachment dispensing location where the needles are aligned with a pair of plungers. The plungers are then inserted into the needles to expel the attachment therefrom. Thereafter, the plungers retract and the shuttle moves back into the attachment severing location to accept another attachment. The shuttle, feed belt, knife blade and plungers are mounted to a head member. The head member is driven between between an attachment dispensing position and a withdrawn position by an electric motor driven assembly.
Although the aforementioned device has performed reasonably well in the dispensing of attachments, it has certain shortcomings. One such shortcoming is that the device not infrequently causes an attachment to be severed asymmetrically (see, e.g., FIGS. 1A and 1B wherein a properly severed attachment 10a and an asymmetrically severed attachment 10b are respectively shown), thereby impairing its utility and/or aesthetic value. The principal reason for this undesired asymmetry is that the feed belt, which is used to advance the attachment through a feed drive and into the pair of needels, is separated from the needles by a rather considerable distance of approximately 6 inches. Consequently, if the feed belt does not properly advance the ladder stock over this 6 inch spacing, one or more improperly severed attachments may be formed.
The shuttle mechanism of the above-mentioned device presents another such shortcoming. As noted above, when the device is in use, the shuttle moves back and forth between an attachment severing position and an attachment dispensing position. To properly align the shuttle at each of the aforementioned positions, mechanical stops are strategically placed to limit movement of the shuttle. The stops, however, do not always function with the timing and positional precision required to precisely place the shuttle at its desired location at the appropriate time.
Another pertinent patent is commonly assigned U.S. Pat. No. 4,533,076. This patent, which is also incorporated herein by reference, discloses another such device for dispensing attachments from continuously connected ladder stock.